A conventional puller contains an operating portion and a plurality of hooking claws away from the operating portion. The operating portion has an abutting post extending outwardly therefrom, and each hooking claw is adjusted to expand outwardly or retract inwardly, the operating portion is provided to adjust the abutting post.
In operation, user operates the operating portion to drive the abutting post, and then the abutting post expands outwardly, thereafter an adjustable screw nut is rotated to adjust a clamping position of the plurality of hooking claws and a driving wheel, and the user has to observe whether the plurality of hooking claws clamp the driving wheel. However, such an operation is troublesome. Also, the clamping position of the plurality of hooking claws and the driving wheel cannot be adjusted exactly, thereby damaging the driving wheel easily.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.